RP (Rapid Prototyping)

446.326A CAD/CAM. RP (Rapid Prototyping). November 05, 2008 Sung-Hoon Ahn School of Mechanical and Aerospace Engineering Seoul National University. MRI 1. 3. 8. From 2D to 3D printing. 2D sheet. 2.5D Prismatic plate. 3D structure. NASA: Printing in Space. Emergency in 2008 summer. FDM1600 test at zero gravity Johnson Space Center & Marshall Space Flight Center 2000. Requirements in Product Development  Functional or aesthetic assessment  Communication aids, visualization  Assemblability checking  25 or 30% of product development budget are spent on physical prototypes and testing  Rapid Prototyping fabricates a part of arbitrary shape directly from CAD model by forming thin layers of the part layer by layer. Introduction to RP  Other name of RP - Layered Manufacturing - Rapid Prototyping and Manufacturing - Solid Freeform Fabrication (SFF).  Group of related technologies that are used to fabricate physical objects directly from CAD data  Add and bond materials in layers to form objects  Offer advantages compared to classical subtractive fabrication methods. Advantages of RP  No need to define a blank geometry  No need to define set-ups and material handling  No need to consider jigs, fixtures, and clamping  No need to design mold and die. General System Configuration of RP. Stereo Lithography Process  Geometry Input : STL file format - Developed for STereo Lithography - De facto standard for RP data - Most CAD systems support STL format. Stereo Lithography Process (cont.)  STL file formats. (a) ASCII. (b) Binary. Typical Errors in STL file. Stair-Step Effect. Surface roughness vs. build time. Support Structures. Issues in RP  Accuracy and Surface Finish  Material - Stereo Lithography Resins - Metals - Ceramics and Paper.  Cost - Equipment - Maintenance.  Time. 1. Stereo Lithography Apparatus (SLA)  Developed by 3D Systems, Inc.  Laser beam will scan the surface following the contours of the slice. SLA-3500. Micro SLA Part Gear. Horse. Turbine. Dog. 2. Selective Laser Sintering (SLS)  Developed by The University of Texas at Austin.  Powders are spread over a platform by a roller  A laser sinters selected areas causing the particles to melt and then solidify. 3. Laminated Object Modeling (LOM)  Developed by Helysis  The undersurface of the foil has a binder that when pressed and heated by the roller causes it to glue to the previous foil.  The foil is cut by a laser following the contour of the slice. Helisys 2030E LOM machine Part envelope size 32"x22"x20". LOM based technique  Paper Lamination Technology(PLT) System. < Kira Solid Center > - Type: PLT-A4 - Model Material: Exclusive use sheet paper (280×190 ×200m) - Paper Thickness: 0.08mm, 0.15mm - Resolution: ±0.05mm (X, Y), ±0.1mm (Z) - Accuracy: ±0.2mm. 4. Fused Deposition Modeling (FDM). Fused Deposition Modeling (FDM). FDM Head. x-axis track heating units. model head support head. z-axis track. foam bed. 5. 3D Printers  Developed at MIT  Parts are built upon a platform situated in a bin full of powder material.. 3D Printing Process. 3-D printing method developed by Sachs and colleagues (2000). 6. Solid Ground Curing (SGC)    . Developed and commercialized by Cubital Ltd. (Israel) Uses a Photopolymer, sensitive to UV-light The vat moves horizontally as well as vertically The horizontal movements take the workspace to different stations in the machine. 7. Shape Deposition Manufacturing (SDM)  Developed by Stanford University/CMU  Uses deposition and milling  Provides good surface finish. Issues in RP Materials  Rapid Fabrication of functional parts - Structural - Optical - Surface Roughness - Electrical - Thermal - Color - ………. FDM Software – Three Levels  STL file – Tessellated Stereolithography file – export from solid modeling package  SSL file – Sliced Layer File, Support Calculation – Proper part orientation can drastically affect build time, support requirements, and part strength.  SML file – Raster, Build Parameters, time estimation. Case study: Collapsible Shovel Head 1. Tessellated (Triangulated) format 4. Road Generation. 2. Vertically Sliced File 5. SML firle. 3. Support Calculation. FDM Build Parameters - Software  Perimeters, Contours, Raster (Road type) - Perimeter: Follows outer shape of current slice - ideal for cosmetic. outer surface - Contour: Follows shape of perimeter on part interior - not commonly used as it leaves gaps - Raster: Standard back and forth part fill - adds strength to part, composite theory (raster angles).  Road width - Dependant on nozzle size and feed rate - ranges from .012 to .0396 for T12 nozzle.  Air Gap - Gap between roads - allows for tightly fused, strong surface, or sparse, quick building fill. Micro Structure of FDM. Part Post-process of FDM. FDM Process. Assembled Part. Resin Infiltration. Raw FDM ABSi. During Infiltration Raw material. 0.6. Infiltration. Infiltration+Sanding. 25. 0.5. Transmissivity(%). Transmissivity(%) .. After Infiltration. 0.4 0.3 0.2 0.1. 20 15 10 5 0. 0 800 760 720 680 640 600 560 520 480 440 400. Wave length(nm). -0.003. 0 Air Gap(inch). 0.003. Flash Memory Reader. CATIA modeling:. FDM process:. 5 hours. 10 hours. Post-process : 24 hours Total prototyping time : 39 hours. Gallery  SLA. Gallery (cont.)  FDM. Gallery (cont.)  FDM. GPS module for PDA. Gallery (cont.)  Z- corp (3D Printer).  SLS. Gallery (cont.)  Z- corp (3D Printer). Gallery (cont.)  Z- corp (3D Printer). Gallery (cont.)  Z- corp (3D Printer). Applications  Architectures. A machine mounted on rails might be used to build multiple houses. Applications (cont.)  Materialization of arts. Lifting the kouros out of the Mammoth. The original Volomandra Kouros and the SLA replica. Applications (cont.)  Medical Domain. Before surgery. After surgery. CT Scan. RP part. Virtual surgery. MRP (Medical rapid prototyping)  3D model creation process 3D Digital Image. Data transfer process. Evaluation of Design :Using CAD Program. RP Medical model validation. RP Medical model production. Tissue Engineering Vacanti, et al. Yan, et al. CAD modeling. RP part. Rehabilitated ear. Applications (cont.)  Micro component. Micro robot by Sandia Lab. Applications (cont.)  Rapid Tooling (RT). Core and cavity sets produced by RapidTool ™. DTM's RapidTool™ process for rapid mold making. Applications (cont.)  Other Examples Patterning with Ceramic. Sensor and Actuator. Artificial Bone and Ear. Electrode ; A. Safari et al. IEEE Artificial bone P. Kumar at al, Ann Arbor. Microreactor Y. Tan et al. Am. Ceram. Soc.. PZT Sensor ; J. E. Smay et al. J. Am. Ceram. Soc. R. Knitter at al. RP Journal. Artificial ear Bio-compatible Material. 3D Nano/Micro Parts  Two-photon Stereolithography (a). (b). SEM images of fabricated islands with (a) actual and (b) exaggerated ratio of height vs. width by controlling both exposure time and laser power simultaneously. Inse t is top v iew of th e s tructure. Fabricated micro-prototypes of a micro rotor. SEM images of fabricated micro-Thinker by doublescanning path. The insets are the same micro-Thinker with various view angles, and the scale bars are 10 ㎛. Hybrid RP System  Hardware  Deposition; Rapid Prototyping. Z axis control.  Cutting; Milling  Hybrid; Both. High speed spindle. Dispenser UV lamp. Microscope. Micro needle. Micro needle. Micro endmill. Micro endmill SPECIFICATIONS. X and Y axis control Granite Base. 3 Axes-stage Dispenser Micro needle Micro tool High speed spindle UV curing system Controller. 1㎛ resolution 15 ~ 700 kPa  140 ㎛ ~ 800 ㎛  100 ㎛ ~ 1000 ㎛ Max. 46,000rpm 0 ~ 400 W, λ = 365 ㎚ PMAC (Multi-tasking board). Hybrid RP System (cont.)  Hybrid process: depositing + machining. High speed spindle. Air cylinder. Micrometer. Barrel I. Barrel II. Micro needle. Micro tool. Conceptual process of NCDS. Hybrid RP System (cont.)  Process planning Deposition. 3D MODEL. Machining. SLICING Part material. NO. DEPOSITION. DEPOSITION. CURING. CURING. HYBRID SYSTEM. CONVENTIONAL DEPOSITON SYSTEM. PROCESS PLANNING. MACHINING. LAST LAYER ? YES. LAST LAYER ?. POST-PROCESS. Support material. Deposition and Machining. Machining. NO. Molding / Casting. Support. YES 3D PART. Part Deposition. Machining Heat Demolding. 90mm. CAD Model and NC Codes Slicing: Slice into 9 layers, layer thickness is 10mm. 90mm. Layer model of a microcone. CAD design of a microcone. Hatching: Parallel line spacing, filling between lines is 10mm. NC Codes for the Cone. Layer 1. Layer 9 Layer 8 Layer 7 Layer 6 Layer 5 Layer 4 Layer 3 Layer 2 Layer 1. Nano Composite Parts  Micro Gear A gear geometry with  2.9mm was fabricated - 5wt% MWCNT + Acrylic resin - Dispensing process using  300㎛ needle micro milling using  100㎛ flat endmill -.  Stapes The smallest bone in human body, width 2.5mm / height 3.5mm - 40wt% Hydroxyapatite + Acrylic resin - Dispensing process using  140㎛ needle micro milling using  100㎛ flat endmill - Mold (using wax) machining → part deposition → surface machining → demolding -. 3.4mm. Microscope picture of microgear.  Fabrication time Parts. Average Time (min). Micro Gear. 2. Stapes. 15. 3.0mm. Geometry of stapes. Scaffold for Bone Growth  Bio-degradable polymer. PLGA 85/15. PLGA 85/15 + 10wt% HA. Size; Φ 5mm × 10mm. Drug Delivery System (DDS)  Specimen for Zero-order Release Test Burst. Drug Delivery Device. Container.  Scaffold Shape of DDS (Controlled Pore Size). Fabricated container and drug delivery device. Fabricated drug delivery device of scaffold shape (15 layers, [0˚8/90˚7], 5mm×5mm). DDS (cont.)  In vivo test with Sprague-dawley Rat 1. Sprague-dawley Rat. 2. Anesthetize mouse. Anesthesia When implantation (100㎎/㎏ for Sprague-dawley Rat) - 25㎎ of Ketamine(90vol%)+Xylazine(10vol%) - 1 ㎖ needle. When picking the specimen - Inhale anesthetize using ether. 3. Remove hairs. Incise back skin. DDS (cont.)  Implantation of DDS - Scaffold type of DDS -  2mm × 2mm size of DDS for implantation. 5-FU/PLGA/HA. - 5-FU(10wt%)/PLGA(85:15)(85wt%)/HA(5wt%). Schematic diagram of scaffold shape of DDS for in vivo. 4. 6. 5. Prepare scaffold DDS. Insert the scaffold. Suture the skin. DDS (cont.)  Collecting implanted DDS form Sprague-dawley rat (a). (b) 40. (c). Cumulative amount of released drug (%). Cylinder Scaffold 30. 20. 10. 0 0. 5. 10. 15. T ime (days). (a) Resection of back skin of the rat, (b) DDS in the back of the rat, and (c) DDS in resected skin.